Bearer for the stationary vanes of rotary motors



April 20, 1943. G. SCHAPER BEARER FOR THE STATIONARY VANES OF ROTARYMOTORS Filed July .17, 194C) 2 Sheets-Sheet 1 INVENTOR Y e. SCH/\PERATTORNEYS April 20, 1943. G. SCHAPER 2,316,813

BEARER FOR THE STATIONARY VANES OF ROTARY MQ'IIORS I Filed July 17,19402 Sheet s-Sheet 2 INVENTOR Y 6. SCH/\PER ATTRNES Patented Apr. 20, 1943BEARER FOR THE STATIONARY VANES OF ROTARY MOTORS Georg Schaper,Mulheim-Ruhr, Germany, as-

signor to Holzwarth Gas Turbine 00.. San

Francisco, Calif.

Application July 17, 1940, Serial No. 345,990 In Germany July 22, 1939Claims.

The stationary vanes of rotary motors propelled by fluids of hightemperature are very often subjected to a maximum of stress by heat.This is especially the case if the whole rim of the wheels is notimpinged by the motive fluid continuously and at a uniform rate but onlya partial contact takes place. In this case there is sufilcient time andopportunity for the moving vanes which rotate with the wheel or drum tobe cooled down at the part of the circumference which does not get intocontact with the motive fluid. This accounts for the fact that theaverage temperature of the moving vanes is considerably below that ofthe stationary vanes. This permits certain conclusions to be drawn withreference to the stress caused by heat. The stationary vanes. however,cannot change their position in relation to the nozzles conducting themotive fluid. They are therefore continuously and without a pausesubjected to the stress exercised by the flow of the motive fluid aslong as the motive fluid flows through the nozzles.

Due attention has been paid to this discovery, and the stationary vanesof older types of turbines have already been provided with an effectivesystem of cooling or have been made of material capable of overcomingwithout any difliculties the increased stress caused by the heat. But itis likewise a fact that not only are the stationaryvanes propersubjected to this increased stress, but also the walls into which thevane.

bases are inserted, in particular the surface which is touched by themotive fluid.

Attempts have been made to meet this stress by securing the cooledstationary vanes to a cooled bearer having as thin walls as possible andattached, preferably by means of welding, to the wheel casing. By thismethod it has been possible to diminish considerably the strainexercised by heat on the walls. However, this arrangement wasresponsible for an inevitable accumulation of material at the pointwhere the vane feet are secured to such a type of bearer. Thisaccumulation of material renders it diflicult for the heat to leave themotive fluid in order to be absorbed by the cooling liquid. This isespecially true if the gases of explosion turbines are the motive fluid.

The present invention is based on the observation that for the purposeof smooth and continuous operation, it will be necessary to overcomealso this insufliciency. According to the invention, the problem issolved by the application of a bearer for the stationary vanes whichconsists of two separate thin-walled rings or ringshaped parts arrangedon both sides of the row or rows of vanes. These rings or ring-shapedparts are connected with one another only by means of the vanes whichthey carry, apart from their connection via the wheel casing in whichthey are placed. This method permits of the (CL Gil-41) construction ofa bearer for the vanes with a minimum of mass and, consequently,eliminates any accumulation of material. This bearer thus makes itpossible for the cooling liquid to get freely and in every directioninto contact with the feet of the vanes. It is thereby also possible tobring the cooling liquid and the material of which the vanes are madeinto as close proximity as possible to the part of the vanes taking onthe heat. This is important because a satisfactory dissipation of theheat depends on as short a distance as possible between the part of thevane taking on the heat and the part releasing it in order that thetemperature drop which is required to lead away the heat may be as smallas possible. The temperature drop de termines the degree by which thetemperature of the vanes must be higher than the temperature of thecooling liquid. In this way it is possible to improve the cooling effecton the feet of the vanes with the aim of decreasing the temperature ofthat part of the vanes which is in the center of the flow of the motivefluid. As a result, the invention contributes toward greater safety inoperation not only of the bearer proper but also the vanes.

The invention will be further described and in greater detail byreference to the accompanylng drawings, in which- Fig. 1 shows thepractical application of the invention -o a bearer of a stationary vaneof an explosion turbine. The bearer is illustrated in cross-section.

Figures 2 to 5 demonstrate, also on the basis of cross section, theindividual stages of construction of the bearer.

Fig. 6 illustrates anexplosion turbine plant in which certain featuresof my improved bearer or carrier for the stationary turbine blades asshown in Fig. 1 are embodied.

In Fig. 1, the reference character I indicates the wheel of the type ofa Curtis wheel, with the two rims 2 and 3, while 4 designates the nozzlepiece which conducts the motive fluid from an explosion chamber and anozzle valve (which are shown in Fig. 6) to the vanes.

The system of vanes consists of two rows of vanes 2 and 3 and the wheelI, as well as of a segment with one row of stationary vanes 5. Thissegment has at least the length of the nozzle arch 4.

According to the invention, the bearer of the stationary vanes isconstructed as follows:

It consists of two separate thin-walled rings or arcuate parts 6 and Iwhich are arranged on both sides of the row of vanes 5 and which, asidefrom being connected with one another via the wheel casing in which theyare placed, have connection with one another only by means of the vaneswhich they carry. I prefer to make this connection by means of weldedcross-ties I the head ends of which coincide with the two arcuatesections 8 and 8" of welding material peripherally arranged. For thepurpose of holding these arcuate sections 8 and 9 the arcuate parts I, Ihave arcuate excavations at l 1 respectively. The feet I of the vanesproject slightly beyond the bordering surface I" and 1 of the coolingliquid canal II. This arrangement accounts for the formation of arcuateniches having angle-shaped cross-section i I, which are filled by meansof rings I! of welding material. In this way the arcuate parts 6 and Ihaving varehor angle-shaped cross sections, respectively, are connectedwith one another in addition to their connection via the turbine casing;the welding seams are marked it and i4.

The feet of the vanes should also have a slot-shaped excavation l5,which may be obtained by milling in a peripheral direction and whichopens into the cooling liquid canal III. This excavation permits thecooling liquid conducted through the cooling liquid canal to be broughtas close as possible to the part 5 of the stationary vanes taking on theheat. The dissipation of heat is furthermore faciltiated by placing (ina manner which in itself is known, see, for instance, the patent toHolzwarth, No. 2,256,479) cores Ii of such heat-conducting material ascopper or the like, in a longitudinal grooveof the vanes 5.

These cores join a base plate l6.

Owing to the fact that the excavation ll extends into both the foot ofthe vane and the core and core base, the cooling liquid has full accessto all heat conducting parts. The flow of heat is facilitated byinsuring metallic continuity between the core and the core base on theone hand, and the vane and the foot of the vane on the other. a

Figures 2 to 5 illustrate the steps of building up such a type of bearerfor the stationary vanes.

Figure 2 is a cross section of an arcuate block of material and containsin itself the cross sections of parts 6 and l. The groove ll with thearcuate excavations 6 and l which serve to hold the welded sections 9and 9 has already been cut into the block. The total excavation l1, l8extends beyond part ll which forms the groove proper to a space which issubsequently occupied by the cooling liquid canal.

Figure 3 shows a ring shaped part which has been worked upon accordingto Figure 2, but after having inserted the vanes I and constructed thecross-ties 9 and the welded sections 9 and 9". It will be observed thatthe cross-ties are made of relatively thin stock, and hence no dangerousaccumulation of material at the base of the vanes occurs; and further,that they increase the rigidity of the connection of the rings orarcuate sections 6 and I and the vanes each with the other. The wholeunit is now rigid enough to be slotted, as shown in Figure 4, whereby itwill be possible to connect the ends of the vane feet 5 and 5"projecting beyond the bordering surfaces 6 and-l with the block byfilling the niches II with rings of welding or soldering material. Bythis construction the surface contacted by the cooling liquid isincreased, the filling also insuring a solid, tight and heat-conductingconnection between the feet of the vanes and the bearer.

The slot-shaped excavations l5 may now be cut in the direction of thecooling liquid canal between the flanks of the vane feet and make itpossible to bring the parts contacted by the cooling agent still closerto the parts of the vanes which receive heat.

According to Figure 5 the lateral arcuate parts 6 and I are thereuponcompleted, except for ma- I ment shown in Figure 1.

Fig. 6 shows a known type of constant volume explosion turbine assemblyin which my improved construction is incorporated. The explosion turbineplant includes one or more constant volume explosion chambers II inwhich a combustible charge of fuel and air is periodically exmoded andthe combustion gases under high temperature and pressure are dischargedinto a nozzle piece or channel 4 upon opening of the male valve ii, thenozzle itself being'shown at 22. The gases flow through the blades ofthe rotor i, being intermediately reversed in the stationary blades I,

and then flow through the channel 28 to theblading of the rotor I, beingfinally discharged at 24. An auxiliary nozzle valve 25 conducts theexplosion gases of lower temperature and pressure, for example, thegases displaced by the scavenging air, directly to turbine I by way ofthe conduit 26. The explosion chambers are fed in known manner by a fuelvalve 2'! and an air valve 2., all of the valves being hydraulicallycontrolled by a pressure oil distributor 28, driven by a motor 30 whichalso drives a pump II,

which feet; oil under pressure to the distributor.

I claim:

1. In a rotary motor operated by a medium of high temperature andincluding a casing and a rotary wheel carrying a plurality of rows ofvanes thereon, the combination of stationary vanes between two rows ofrotary vanes, and a bearer for the stationary vanes comprising twoarcuate sections, arranged one on each side oi the stationary row ofvanes, said sections beinl anchored within the wheel casing and beingadditionally connected with each other by way of the stationary vaneswhich they carry.

2. A bearer construction as set forth in claim 1 wherein the arcuatesections are connected with the vanes by way of peripherally extendingwelding seams, and are additionally connected with each other only byway of cross-ties filling gaps between the vanes and connected with thearcuate sections.

3. Abearer construction as set forth in claim 1, wherein the feet of thestationary vanes project beyond the sections, the angular space betweensuch sections and the projecting vane feet being filled with metal so asto establish a solid, tight and heat conducting connection between thevanes and the bearer.

4. A construction as set forth in claim 1, wherein the vane feet areprovided with slot-shaped peripheral excavations between the flanks ofsaid feet which are connected with the arcuate sections, said sectionsconstituting part of the wall of a cooling canal and said excavationsextending This results in the arrange

